The present invention relates to a so-called projection-type vehicular headlamp. More particularly, the present invention relates to a projection-type vehicular headlamp which provides a low-beam light distribution pattern having a predetermined cut-off line.
Generally, in a projection-type vehicular headlamp a reflector reflects light from a light source mounted on an optical axis extending in the longitudinal direction of the vehicle forward in the direction of the optical axis, and the reflected light is radiated forward of the lamp through a projection lens provided ahead of the reflector.
When this projection-type vehicular headlamp is configured for use in generating a low beam, as shown in FIG. 6, the light distribution pattern P′ has a cut-off line CL′ formed by providing a shade 6 between the projection lens 2 and the reflector 4 to block part of the light reflected from the reflector 4.
The contrast between the area above the cut-off line CL′ and the area below the cut-off line CL′ in the low-beam light distribution pattern P′ is considerably high since the cut-off line CL′ is formed as a sharp reverse projection image of the shade 6.
Accordingly, when, for example, the vehicle on which the headlamp is mounted is moving from a downward slope to a flat road surface, the road surface ahead of the vehicle may be dark and visibility on the distant road surface may be insufficient (depending on vehicle speed), which makes it difficult for a driver to safely operate the vehicle. Moreover, if the cut-off line CL′ moves up and down slightly due to pitching of the vehicle or the like, the light intensity changes abruptly, which may inflict glare on drivers of oncoming vehicles.